Magneto



R. E. PHELON June 14, 1955 MAGNETO INVENTOR ATTORNEY 3 Sheets-Sheet l RUSSELL E. PHEL ON Filed Jan. 18 1951 June 14, 1955 R. E. PHELON 2,710,929

MAGNETO Filed Jan. 18, 1951 3 Sheets-Sheet 2 INVENTOR RUSSELL E. PHEL ON ATTORNEY June 14, 1955 R. E. PHELON 2,710,929

MAGNETO Filed Jan. 18 1951 3 Sheets-Sheet 5 INVENTOR RUSSELL E PHELO/V ATTORNEY F/GZZ F/G. 23

United States Patent MAGNETO Russell E. Pheion, Longmeadow, Mass.

Application January 18, 1951, Serial No. 206,636

8 Claims. (Cl. 310--70) The invention relates to high tension magnetos, and while the invention is not necessarily so limited it is particularly applicable to small magnetos adapted for use with internal combustion engines.

One object of the invention is to provide a magneto which is much smaller than a conventional magneto of the same capacity. This object is attained in part by providing a core structure having two separate primary coils and two separate secondary coils as has heretofore been proposed, but the provision of separate coils has heretofore been unsatisfactory by reason of the difficulty encountered in properly insulating the connecting wires between them, more particularly the high tension wires connecting the secondary coils. In accordance with the invention a single unitary body of insulating material is molded in place so as to surround and enclose the primary and secondary coils and so as to preferably also surround and enclose the connecting wire or wires between them.

Another object of the invention is to provide a magneto having its parts so constructed and arranged that a spark can be obtained at only a predetermined rotative position, thus avoiding false or maverick sparks at other positions. This object of the invention is attained by providing a peculiar arrangement of and relationship between the core faces of the core structure and the pole pieces of the field structure, this arrangement and relationship providing a maximum flux change in the cores of the core structure at one position in each relative rotation while causing only relatively small flux changes at any other positions during each relative rotation.

Other objects of the invention will be apparent from the drawings and from the following description and claims.

In the drawings l have shown in detail different embodiments of the invention, but it will be understood that various changes may be made from the constructions shown, and that the drawings are not to be construed as defining or limiting the scope of the invention, the claims forming a part of this specification being relied upon for that purpose.

0f the drawings:

Fig. l is a vertical transverse sectional view of a magneto embodying the invention, the section being taken along the broken line 11 of Fig. 2.

Fig. 2 is a vertical longitudinal sectional view taken along the line 2-2 of Fig. 1.

Figs. 3 and are side and front views of a coil unit constituting a part of the stator.

Fig. 5 is a diagram of electrical connections.

Fig. 6 is a view similar to Fig. 1 but showing an alternative rotor, the stator being omitted.

Figs. '7 to are schematic views showing the rotor in various positions.

Fig. 21 is a view similar to Fig. 1 but showing another alternative embodiment of the invention.

Figs. 22 and 23 are views similar to Figs. 3 and 4 ice and showing a coil and condenser unit constituting a part of the rotor as shown in Fig. 21.

Figs. 24, 25 and 26 are diagrams of alternative electrical connections.

A magneto embodying the invention comprises two relatively rotatable structures, one being a field structure and the other being a generating coil and core structure, herein sometimes designated as the core structure. The relative arrangement of these structures may be widely varied within the broader aspects of the invention, but in order to illustrate the invention a presently preferred embodiment is shown wherein the core struc ture is centrally located and is stationary, being herein sometimes designated as the stator, and wherein the field structure surrounds the core structure or stator and is rotatable, being herein sometimes designated as the rotor.

The core structure or stator of the magneto is carried by a frame iii having a central opening through which a rotatable shaft 12 extends, the shaft being mounted in a suitable bearing which is not shown. The shaft 32 may be an extension of the crankshaft of the engine with which the magneto is to be used, and in any event it is rotated in timed relationship with the engine. The core structure comprises a plurality of magnetic core elements having pole faces at their ends. Preferably the core elements are separate cores. The invention is not necessarily limited as to the number of core elements or cores, but when there are separate cores there are at least two of them such as the cores and in, these cores having at least four pole faces such as iii, 12%, 22, and 24. The cores are preferably laminated and their pole faces are arcuate, being concentric with a central axis which is the axis of the shaft 12. The said pole faces are equidistant from the said central axis, and they preferably extend circumferentially to approximately equal extents. The cores 14 and 16 are suitably connected with the frame Ill as for instance by means of screws 26, 26, and 28, 23, spacers being associated with the screws for holding the cores at proper distances from the frame.

A primary coil 34) surrounds the core 34, the ends of the coil being spaced from the pole faces of the core. A similar primary coil 32 surrounds the core 16, the ends of the coil being spaced from the pole faces of the core. A secondary coil 34 surrounds the coil 38 and the core 14, the coil 34 preferably being somewhat shorter than the coil 39. A similar secondary coil 36 surrounds the coil 32 and the core 16, the coil 36 preferably being somewhat shorter than the coil 32. Each primary coil has a relatively small number of turns, as for instance 100, and each secondary coil has a relatively large number of turns, as for instance 5,000.

Different wiring connections may be provided, one such connection being shown in Fig. 5. The primary coils 30 and 32 may be connected in parallel or in series and they are shown as connected in series by a wire 38. The secondary coils 34 and 36 may be connected in parallel or in series and they are shown as connected in series by a Wire 40. A wire 42 extends from one end of one primary coil, as for instance the coil 38, this wire being grounded at 44. A Wire 46 extends from one end of one secondary coil, as for instance the coil 34, this wire being grounded at 48. Extending from the opposite end of the other primary coil 32 is a wire 59 which is connected with a movable breaker point 517., a companion stationary breaker point 54 being provided which is grounded at 56. In accordance with customary practice a condenser 57 is connected in parallel with the breaker points, it being so connected by means of wires 53 and 59. Extending from the opposite end of the other secondary coil 36 is a high tension wire till which is connected with a sparking device such as the spark plug 62 of the engine.

The breaker point 52 is carried by a rocker arm 64 pivoted at 66 on the frame 10. The rocker arm 64 has an extension 68 which is engaged by a cam 70 secured to the shaft 12. A spring 72. serves to bias the arm 64 to move the point 52 into engagement with the point 54, and this spring, or an auxiliary conductor associated therewith, serves in conjunction with a connecting screw 73, to provide an electrical connection between the wire 50 and the said point 52. When the shaft 12 is rotated thev cam 70 oscillates the rocker arm 64 to make and break the electrical connection between the breaker points 52 and 54.

The provision in the stator of two core elements or two separate cores each with its own primary and secondary coils makes it possible for the magneto to be much smaller than would otherwise be necessary. In order to obtain the required spark intensity, predetermined total numbers of coil turns must be provided. If the required numbers of turns were provided in one primary coil and in one secondary coil the outer diameter of the secondary coil would be large and the surrounding rotor would necessarily be correspondingly large in diameter and also in the axial direction. With the present construction each coil is only approximately one-half as large and the two pairs of coils are so arranged that the magneto dimensions are greatly reduced. Furthermore, a certain cross sectional area ofiron is necessary in the core portions which extends through the coils in order to provide a magnetic path of sufiiciently low reluctance to accommodate the requisite number of units of magnetic flux through the coils. By providing two cores and two flux paths the length of wire in each turn of each coil is reduced is also the outer diameter of each coil.

When there are two pairs of separate primary and secondary coils surrounding two core elements or two separate cores, a serious problem is presented as to the suitable insulation of wires, such as 38 and 40, extend ing between the coilsof the two pairs, and more particularly as to the suitable insulation of the high tension wire, such as 40, extending between the two secondary coils. In order to properly insulate the said wires and in. order to obtain other advantages, a single unitary body 74 of insulating material is preferably molded around the coils 30, 32, 34 and 36-and around the connecting wires 38 and 49, as more clearly shown in Figs. 3 and 4. During the molding of the body 74 the coils and the wires connected therewith are suitably held in proper relationship with each other. The cores l4 and 16 may be in place during molding or the holes through the molded body for receiving the cores may be otherwise formed. The molded body engages and fits each core element or core between each pole face thereof and the adjacent ends of the corresponding primary and secondary coils.

When there are two core elements or two separate cores angularly related as shown, the body 74 comprises two relatively large main portions 76 and 77 which respectively surround the coils 3t) and 34 and the coils 32 and 36. The end portions of the cores i4 and 16 project from the said main portions. The body 74 also comprises an integral smaller portion 78 which connects the two said main portions and which encloses the wires 33 and 40.

Preferably, the molded body 74 has a rearward projection 79 which is molded around and encloses a wire constituting a portion of the high tension connection 6t? with the spark plug 62. The wire is connected with a suitable terminal member 84) molded in place in the projection and adapted for the connection of a conductor wire 81 as shown in Fig. 2.

It will be seen that the coils and the connecting wires therefor and the molded body which surround and enclose them constitute a unit adapted for use in a magneto. In such a unit the molded body has openings therethrough for the reception of the cores.

In accordance with one phase of the invention, the cores 14 and 16 are of such sizes and positions that their pole faces have an angular spacing which is nonsymmetrical with respect to any selected plane through the central axis. The plane through the central axis and midway between the pole faces 18 and 24 may be taken as an example. It will be seen that the pole faces 18 and 2% at one side of the said plane and the pole faces 24 and 22 at the other 'side of the said plane are differently spaced angularly. Stated otherwise, the angular spacing between each two immediately adjacent pole faces is substantially different from the angular spacing between any other two immediately adjacent pole faces. Preferably and as shown, the two cores 14 and 16 are of different lengths and are at an angle to each other. As shown the spacing between the pole faces 24 and 18 is the smallest with a subtended angle a, the spacing between the pole faces 18 and 20 is larger with a subtended angle b, the spacing between the pole faces 22 and 24 is still larger with a subtended angle 0, and the spacing between the poles 20 and 22 is the largest with a subtended angle d.

The rotatable field structure or rotor of the magneto comprises pairs of pole pieces corresponding in number to the cores of the core structure. When there are two cores f4 and 16 there are two pairs of pole pieces 82, 34 and 86, 88. Magnets are associated with the pole pieces for providing opposite polarity in each two immediately adjacent pole pieces. As shown, a permanent magnet is interposed between the pole pieces 82 and 34 and a permanent magnet 92 is interposed between the pole pieces 86 and 88. The inner pole faces of the several pole pieces are arcuate and are concentric with the aforesaid central axis which is the axis of the shaft 12. The said inner pole faces are closely adjacent but slightly spaced from the arcuate pole faces 18, 20, 22 and 24 of the cores 14 and 16. The two magnets 99 and 92 are charged circumferentially and in the same circumferential direction so that the pole pieces 82, 84, 86 and 88 have opposite polarity. The polarity of the pole pieces 32 and 86 may be positive or north and the polarity of the pole pieces 84 and 88may be negative or south.

The several pole pieces are notched to receive the magnets, the magnets being spaced outwardly from the inner pole faces of the pole pieces. Substantially uniform magnetic gaps are provided between the adjacent ends of the several pole pieces.

The several pole pieces and magnets are supported and rotated by means of a housing 94 formed of nonmagnetic metal and secured to the shaft 12. As shown, the housing 94 is a die casting which is cast round the pole pieces and the magnets. The housing is provided with a hub 96 having a central aperture for receiving the shaft.

The pole pieces 82, 84, 86 and 88 are of substantially different lengths so as to subtend substantially different arcs. The lengths of the pole pieces are such that the centers of the magnetic gaps between them have an angular spacing which is nonsymmetrical with respect to any plane through the central axis. With respect to a particular plane, such as that through the axis and through the center of the magnetic gap between the pole pieces 82 and 88, the nonsymmetrical angular spacing is approximately the same as the before-described nonsymmetrical spacing of the core pole faces with respect to the said plane through the axis and midway between the pole faces 18 and 22. This will be readily apparent when the field structure is in the rotative position shown in Figs. 1 and 20. Stated otherwise, the angular spacings between the centers of the said magnetic gaps are approximately the same as the aforesaid angular spacings between the pole faces of the cores. The lengths of the pole pieces are such that the several pole pieces plus one-half of the two immediately adjacent gaps respectively subtend the aforesaid arcs a, b, c and d.

An alternative field structure is shown in Pig. 6. There are four pole pieces 95, 100, 102 and 104 respectively similar to the pole pieces 82, 84, 86 and 88. In addition to the magnets 90 and 92, two other similar magnets 1416 and 108 are provided, these being positioned respectively between the pole pieces 160 and 192 and the pole pieces 104 and 98 which pole pieces are notched to receive the magnets. The magnets 196 and 108 are charged in directions opposite to the directions of charge of the magnets 90 and 92. The polarities of the pole pieces 93, 1%, 1322 and 1M are the same as previously described for the pole pieces 82, 84, 86 and 88, and the additional magnets 106 and 108 merely serve to augment the action of the magnets 90 and 92.

When a circuit is established through the primary windings or coils 30 and 32, current is induced th rein proportionately to changes in the net total flux in one rotative di rection in the two cores 14 and 16. The net changes in flux at various positions will be more readily understood by reference to the schematic views in Figs. 7 to 20. These views show the rotor in succ ssively different rotative positions, rotation being in the clockwise direction. The said views show the field structure illustrated in Fig. 1.

In referring to Figs. 7 to 20 the directions of flux in the cores 14 and 16 will for convenience be stated to be clockwise and counterclockwise. The terms are intended to designate the flux directions with respect to the central axis and not otherwise. For example, in Fig. 7 the flux direction in the core 14 is clockwise with respect to the central axis, although the core is a part of a magnetic circuit including the pole piece 84 and the magnet 9t? and the pole piece 82 in which circuit the flux direction is counterclockwise.

Fig. 7 shows the field structure in a rotative position somewhat beyond that shown in Fig. l. The Fig. 7 position is that immediately following the generation of a spark at the spark plug 62 as hereinafter explained, the breaker points 52 and 54 having been separated. The core 14 has south polarity at the right and north polarity at the left, the flux therein being clockwise. The core 16 has north polarity at the lower end and south polarity at the upper end, the flux therein being clockwise. The net flux is clockwise and at the maximum.

In the Pig. 8 position the core 14 has south polarity at each end and has little or no flux. The core 16 still has north polarity at the lower end and south polarity at upper end, the flux therein remaining clockwise. The net flux is clockwise and is approximately one-half of the maximum.

In the Fig. 9 position the core 14 has north polarity at the right and south polarity at the left, the flux therein being counterclockwise. The core 16 has north polarity at the lower end and south polarity at the upper end, the flux therein being clockwise. Inasmuch as the flux directions are opposed, the net flux is approximately Zero.

In the Fig. 10 position the core 14 still has north polarity at the right and south polarity at the left, the flux therein remaining counterclockwise. The core 16 has north polarity at each end and has little or no flux. The net flux is counterclockwise and is approximately onehalf of the maximum.

In the Fig. 11 position the core 14 has south polarity at each end and has little or no flux. The core 16 still has north polarity at each end and continues to have little or no flux. The net flux is approximately zero.

In the Fig. 12 position the core 14 still has south polarity at each end and continues to have little or no flux. The core 16 has south polarity at the lower end and north polarity at the upper end, the flux therein being counterclockwise. The net flux is counterclockwise and approximately one-half of the maximum.

In the Fig. 13 position the core 14 has south polarity at the right and north polarity at the left, the flux therein ti being clockwise. The core 16 still has south polarity at the lower end and north polarity at the upper end, the flux therein remaining counterclockwise. Inasmuch as the flux directions are opposed, the flux is approximately zero.

In the Fig. 14 position the core 14 still has south polarity at the right and north polarity at the left, the flux therein remaining clockwise. The core 16 has north polarity at each end and has little or no flux. The net flux is clockwise and is approximately one-half of the maximum.

In the Fig. 15 position the core has north polarity at each end and has little or no fiux. The core 16 still has north polarity at each end and continues to have little or no flux. The net flux is approximately zero.

In the Fig. 16 position the core 14 still has north polarity at each end and continuues to have little or no flux. The core 16 has north polarity at the lower end and south polarity at the upper end, the flux therein being clockwise. The net flux is clockwise and approximately one-half of the maximum.

in the Fig. 17 position the core 14 still has north polarity at each end and continues to have little or no flux. The core 16 has south polarity at each end and has little or no flux. The net flux is approximately zero.

In the Fig. 18 position the core 14 has north polarity at the right and south polarity at the left, the flux therein being counteclcckwise. The core 1 6 still has south polarity at each end and cont nues to have little or no flux. The net flux is count ockwise is approximately one-halt of the in the Fig. 19 position the core has north polarity at the right and south polarity at the left, the iiux therein remaining counterclockwise. The core 16 has south polarity at the lower end and north polarity at the upper end, the flux therein being counterclockwise. The net flux is a ain at the maximum, but is in the opposite direction from that shown in Fig. 7.

From the foregoing detailed description it will be apparent that as the field structure rotates from the position shown in Fig. 7 through the successive positions shown in Figs. 8 to 19 there are various chan es in the net flux rrom a maximum in one direction, as shown in Fig. 7, to a maximum in the opposite direction, as shown in Fig. 19. However, each individual net change is only one-half of the maximum flux in a given direction and the net flux in each of the intermediate positions shown in Figs. 8 to 18 is either approximately zero or approximately one-half of the maximum net flux. This will be more readily understood from the following table wherein flux in the clockwise direction is regarded as positive and wherein the maximum flux in each core is regarded as unity:

With the flux at its maximum in the counterclockwise direction as shown in Fig. 19, the field structure or rotor rotates to the Fig. 20 position which is intermediate the Fig. 19 and Fig. 7 positions, and as it so rotates the cam 76 eiiects movement of the movable breaker point 52 to make or close the circuit through the primary coils and 32. The closing of the circuit serves to hold the maximum fiux which has been established in the cores in one direction, that is, in the counterclockwise direction. As the rotor passes through the Fig. 20 position the direction of flux is suddenly reversed from the maximum in the counterclockwise direction as shown in Fig. 19 to the maximum in the clockwise direction as shown in Fig. 7, and the breaker point 52 is moved by the to break or open the circuit. The sudden reversal of flux from the maximum in one direction to the maximum in the opposite direction constitutes a maximum change in flux, this maximum flux change occurring upon the breaking of the circuit through the primary coils. The said maximum flux change induces a surge of high potential current in the series connected secondary windings which high potential current produces a spark at the spark plug 62. Following the breaking of the circuit, the rotor rotates to the Fig. 7 position and the described cycle is repeated indefinitely.

With magnetos as heretofore constructed, changes in flux sometimes occur at intermediate positions which changes are large enough to induce false or maverick sparks without the making and breaking of the circuit in the primary coil or coils. By reference to the foregoing table and the foregoing description it will be seen that with the present construction the spark is generated during the maximum net flux change from -2 to +2 at the Fig. 20 position, there being a net flux change of 4. At no other position during the cycle does the net flux change exceed 1, that is, one-fourth ofthe maximum change. It is therefore apparent that there is no possibility of a false or maverick spark at any intermediate position in the cycle.

Fig. 21 shows an alternative embodiment of the invention which may be substantially identical with that shown in Figs. 1 and 2 except as to the molded body and the parts surrounded and enclosed thereby. in the construction shown in Fig. 21, the condenser such as 57 is surrounded by and enclosed within the same molded body which surrounds and encloses the coils. in its broader aspects this phase of the invention is not limited to the provision within the molded body of two primary coils and two secondary coils.

As illustrated, the cores 14 and 16 and the several coils 3t 32, 34 and 36 and the connections therefor are or may be the same as previously shown and described. A molded body 98 is provided which is similar to the molded body 74 and which similarly encloses the coils and their connections. The body 93 differs from the body 74 in that it is also molded around and encloses the condenser 57. Preferably, the condenser is located at a connecting portion 101) which is similar to the con necting portion 78. The body 98 is molded around portions of the wires 55 and 59 which are connected with the condenser. One of the wires, which may be the wire 58, is suitably connected with the movable breaker point 52, it being shown as held by the screw '73 which holds the wire 50. The other wire 53 is suitably grounded, this wire being shown as engaged with one of the screws 26 which holds the core 14. Thus the condenser is con nected in parallel with the breaker points as shown in Fig. 5.

The positioning of the condenser within the molded body additionally conserves space, particularly as it makes it unnecessary to provide a separate mounting means for the condenser.

Fig. 24 shows a diagram of electrical connections which is alternative to that shown in Fig. 5. Except as to the wiring, the construction may be either that shown in Figs. 1 to 4- or that shown in Figs. 21 to 23. The primary coils 3t and 32 are connected in series by the wire 38 and they are connected with the movable breaker point 52 by the wire St). The secondary coils 34 and 36 are not connected in series and each of them has an independent circuit. The secondary coil 34 is grounded at one end and is connected at the other end by means of a high tension wire 102 with a sparkplug 104. Similarly,

the secondary coil 36 is grounded atone end and is connected at the other end by means of a high tension Wire 1116 with a spark plug 108'. The coils 30, 32, 34 and 36 and the wire 33 and portions of the other connecting wires, and optionally the condenser 57, may be surrounded by and enclosed within a single molded body such as 7- 1 or 93; The manner of operation is substantially the same as that previously described, except that sparks are generated at two spark plugs instead of at only one spark plug.

Fig. 25 shows another diagram of electrical connections which is also alternative to that shown in Fig. 5. Except as to the wiring, the construction may be either that shown in Figs. 1 to 4 or that shown in Figs. 21 to 23. The primary coils 30 and 32 are connected in series by the wire 33 and the secondary coils 34 and 36 are connected in series by the wire 46. The secondary coils are connected by the high tension wire 61) with the spark plug 62 in the same manner as shown in Fig. 5. The opposite ends of the primary coils are grounded by wires 42 and and the breaker point 52 is connected by a wire 111 with the wire 38 which extends between the two primary coils. The coils 3b, 32, 34 and 36 and the wires 38 and 40 and portions of the other connecting wires, and optionally the condenser 57, may be surrounded by and enclosed within a single molded body such as 74 or 98. The manner of operation is substantially the same as that previously described.

Fig. 26 shows another diagram of electrical connections which is also alternative to that shown in Fig. 5. Except as to the wiring, the construction may be similar to that shown in Figs. 1 to 4 or to that shown in Figs. 2l to 23. While the construction may be similar, it necessarily differs in that there are two sets of breaker points 112, 114 and 116, 118 and two condensers 120 and 122. The primary coil 30 is grounded at one end and it is connected at the other end by means of a wire 124 with the movable breaker point 112 of one set. The secondary coil 34 is grounded at one end and is connected at the other end by means of a high tension wire 126 with a spark plug 128. The primary coil 32 is grounded at one end and it is connected at the other end by means of a wire 130 with the movable breaker point 116 of the other set. The secondary coil 36 is grounded at one end and is connected at the other end by means of a high tension wire 132 with a spark plug 134. It will be seen that with the construction shown in Fig; 26 there are two entirely separate spark generating means. The

coils 30, 32, 34 and 36 and portions of the several connecting wires, and optionally the condensers 120 and 122, may be surrounded by and enclosed within a single molded body such as 74 or 98. The manner of operation is similar to that previously described, but the construction does not have all of the advantages incident to the avoidance of maverick sparks as fully explained in connection with Figs. 7 to 20.

The invention claimed is:

1. In a magneto, the combination of a stationary frame, a rotatable drive shaft projecting forwardly through an opening in the frame, a rotatable annular field structure carried by the drive shaft and located at the front of the frame, a stator including two core elements carried by the frame at the front thereof and within the rotatable field structure which core elements have pole faces incooperative relationship with the said field structure, the said core elements being located at east partly at opposite sides of the said shaft, two primary coils constituting a pair and respectively surrounding the said core elements and located at least partly at opposite sides of the said shaft, two secondary coils constituting a pair and respectively surrounding the said core elements and located at least partly at opposite sides of the said shaft, a conducting wire extending between and electrically connected with the coils of one pair which wire is'spaced'from the said shaft, anda single bodyiof'" insulating material molded in place and comprising two relatively large main portions spaced from the said shaft and located at least partly at opposite sides thereof each of which main portions surrounds and encloses one primary coil and one secondary coil, the said molded body also comprising a smaller portion spaced from the said shaft and extending between the said main portions which smaller portion surrounds and encloses the said conducting wire.

2. In a magneto, the combination of relatively rotatable core and field structures, the said core structure comprising two cores having pole faces at their ends which are at uniform distances from the axis of relative rotation and which have a nonsymmetrical angular spacing with respect to any selected plane through the said axis and the said core structure also comprising primary coils surrounding the respective cores and secondary coils surrounding the primary coils, and the said field structure comprising four pole pieces having arcuate pole faces positioned for relative rotation closely adjacent the aforesaid pole faces of the cores which pole pieces have magnetic gaps between them and are of such lengths that the centers of the said magnetic gaps have a nonsymmetrical angular spacing with respect to a plane through the said axis which is approximately the same as the said nonsymmetrical spacing of the said core faces and the said field structure also comprising magnets serving to provide opposite polarity in each two immediately adjacent pole pieces, and means operable during each rotation for making and breaking a circuit through the said primary coils when all four of the said magnetic gaps between the pole pieces are approximately in register respectively with the four pole faces of the two cores.

3. In a magneto, the combination of relatively rotatable core and field structures, the said core structure com prising two cores having pole faces at their ends which are at uniform distances from the axis of relative rotation and which are so spaced angularly that the distance between each two adjacent pole faces is substantially different from that between any other two adjacent pole faces and the said core structure also comprising primary coils surrounding the respective cores and secondary coils surrounding the primary coils, and the said field structure comprising four pole pieces having arcuate pole faces positioned for relative rotation closely adjacent the aforesaid pole faces of the cores which pole pieces have magnetic gaps between them and are of such lengths that the angular spacings between the centers of the said magnetic gaps are approximately the same respectively as the angular spacings between the several pole faces of the said cores and the said field structure also comprising magnets serving to provide opposite polarity in each two immediately adjacent pole pieces, and means operable during each rotation for making and breaking a circuit through the said primary coils when all four of the said magnetic gaps between the pole pieces are approximately in register respectively with the four pole faces of the two cores.

4. In a magneto, the combination of a stator comprising two cores having pole faces at their ends which are at uniform distances from a central axis and which have angular spacing which is nonsymmetrical with respect to any selected plane through the said axis, the said stator also comprising primary coils surrounding the respective cores and secondary coils surrounding the respective cores, a rotor rotatable about the said central axis and comprising four pole pieces having arcuate pole faces concentric with the said axis and positioned for rotation in a path closely adjacent the aforesaid pole faces of the cores which pole pieces have magnetic gaps between them and are of such lengths that the angular spacings between the centers of the said magnetic gaps have a nonsymmetrical angular spacing with respect to a plane through the said axis which is approximately the same as the said nonsymmetrical spacings of the said core faces,

the said rotor also comprising magnets serving to provide opposite polarity in each two immediately adjacent pole pieces, and means operable during each rotation of the rotor for making and breaking a circuit through the said primary coils when all four of the said magnetic gaps between the pole pieces are approximately in register respectively with the four pole faces of the two cores.

5. In a magneto, the combination of a stator comprisnng two cores having pole faces at their ends which are at uniform distances from a central axis and which are so spaced angularly that the distance between each two adjacent pole faces is substantially different from that between any other two adjacent pole faces, the said stator also comprising primary coils surrounding the respective cores and secondary coils surrounding the respective cores, a rotor rotatable about the said central axis and comprising four pole pieces having arcuate pole faces concentric with the said axis and positioned for rotation in a path closely adjacent the aforesaid pole faces of the cores which pole pieces have magnetic gaps between them and are of such lengths that the angular spacings between the centers of the said magnetic gaps are approximately the same respectively as the angular spacings between the several pole faces of the said cores, the said rotor also comprising magnets serving to provide opposite polarity in each two immediately adjacent pole pieces, and means operable during each rotation of the rotor for making and breaking a circuit through the said primary coils when all four of the said magnetic gaps between the pole pieces are approximately in register respectively with the four pole faces of the two cores.

6. In a magneto, the combination of a stator comprising two cores of difierent lengths and at an angle to each other which cores have pole faces at their ends which are at uniform distances from a central axis, the said pole faces by reason of the different lengths of the cores and their angular relationship being so spaced angularly that the distance between each two adjacent pole faces is substantially different from that between any other two adjacent pole faces, the said stator also comprising primary coils surrounding the respective cores and secondary coils surrounding the respective cores, a rotor rotatable about the said central axis and comprising four pole pieces having arcuate pole faces concentric with the said axis and positioned for rotation in a path closely adjacent the aforesaid pole faces of the cores which pole pieces have magnetic gaps between them and are of such lengths that the angular spacings between the centers of the said magnetic gaps are approximately the same respectively as the angular spacings between the several pole faces of the said cores, the said rotor also comprising magnets serving to provide opposite polarity in each two immediately adjacent pole pieces, and means operable during e2-n rotation of the rotor for making and breaking a c' cuit through the said primary coils when all four of the s i magnetic gaps between the pole pieces are in register respectively with the four pole faces of the two cores.

7. In a magneto, the combination of a stator cone prising two cores having pole faces at their ends rvh' are at uniform distances from a central axis and which t it, so spaced angularly that the distance between each two adjacent pole faces is substantially different from that between any other two adjacent pole faces, the said stator also comprising primary coils surrounding the respective cores and secondary coils surrounding the respective cores, a rotor rotatable about the said central axis and comprising four pole pieces having arcuate pole faces con-- centric with the said axis and positioned for rotation in a path closely adjacent the aforesaid pole faces of the cores which pole pieces have magnetic gaps between them and are of such lengths that the angular spacings between the centers of the said magnetic gaps are approximately the same respectively as the angular spacings between the several pole faces of the said cores, the said rotor also comprising four permanent magnets interposed between the respective pole pieces which magnets are charged circumferentially with alternate magnets charged oppositely so as to provide opposite polarity in each two immediately adjacent pole pieces, and means operable during each rotation of the rotor for making and breaking a circuit through the said primary coils when all four of the said magnetic gaps between the pole pieces are in register respectively with the four pole faces of the two cores.

8. In a magneto, the combination of a stator comprising two cores having pole faces at their ends which are at uniform distances from a central axis and which are so spaced angularly that the distance between each two adjacent pole faces is substantially different from that between any other two adjacent pole faces, the said stator also comprising two primary coils constituting a pair and respectively surrounding the said cores and two secondary coils constituting a pair and respectively surrounding the said cores with a wire connecting the coils of one pair and the said stator further comprising a single unitary body of insulating material molded in place and surrounding and enclosing both of the said primary coils and both of the said secondary coils and also surrounding and enclosing the said connecting wire, a rotor rotatable about the said central axis and comprising four pole pieces having arcuate pole faces concentric with the said axis and positioned for rotation in a path closely adjacent the aforesaid pole faces of the cores which pole pieces have magnetic gaps between them and are of such lengths that the angular spacings between the centers of the said magnetic gaps are approximately the same respectively as the angular spacings between the several pole faces of the said cores, the said rotor also comprising magnets serving to provide opposite polarity in each two immediately adjacent pole pieces, and means operable during each rotation of the rotor for making and breaking a circuit through the said primary coils when all four of the said magnetic gaps between the pole pieces are approximately in register respectively with the four pole faces of the two cores.

References Cited in the file of this patent UNITED STATES PATENTS 1,224,535 Harnm May 1, 1917 1,282,114 Oglesby Oct. 22, 1918 1,333,004 Vaughn May 9, 1920 1,427,324 Priestly Aug. 29, 1922 1,921,111 Apple Aug. 8, 1933 2,446,761 Harmon Aug. 10, 1948 

